WPS: Do not indicate PBC overlap for the same BSS
Even if the UUID would have a mismatch, e.g., due to no UUID known for
the target in a new WPS PBC instance, do not indicate PBC session
overlap if the BSSID is same in the two entries. This should not really
happen in normal use cases, but can happen at least in some test
scenarios where the same BSSID is used in consecutive test cases and the
old BSS entry remains in cfg80211 cache.
Signed-off-by: Jouni Malinen <j@w1.fi>